Low Carbon Heating

A Step along the Road to Zero Carbon – by Darrell Marchand

Graham Brown has written about solar energy and how we can incorporate this into our homes to generate zero-carbon electricity to power our lights and appliances.

The other main source of carbon emissions from our homes is from the generation of heat and hot water. In this part of the country, primarily this comes from burning natural gas in boilers. Natural gas is a carbon fuel – less carbon intensive than oil or coal, but a carbon fuel nonetheless. If there is any chance of meeting the Government’s target of achieving net zero carbon emissions by 2050, we simply have to move away from this fuel source for heating.

But, in looking at what we can do in our own homes, the first step has to be to manage the amount of energy we use. There are a number of actions we can take and you have probably heard them many times over the years. For many houses, they are still relevant, however. 

Simple and inexpensive things like draught-stripping around doors and windows to reduce the amount of cold air getting in and heat getting out and setting your main thermostat to a level that reduces overheating. 

More expensive things such as insulation (walls, roofs and sometime floors) can generate good energy savings and return on investment as can thermostatic radiator valves which regulate the amount of heat being emitted by a radiator based on the temperature in that room. More modern controls have been promoted in recent times – for example, ones that let you control your heating via an app on your phone – and these may be worth investigating. Of course, regular servicing of your boiler is sensible on safety grounds and it will maintain your boiler’s operating efficiency. On top of these options, a smart meter on your gas supply will provide you with information about how much you are using when and how much that is costing – a good way of monitoring and managing your use. If you don’t yet have one, contact your gas supplier and ask them to install one at your home (they are free).

Replacing your windows with more efficient versions are rarely viable on energy-saving grounds alone but as part of a wider package of solutions can be worthwhile and looking for the most efficient is certainly worth considering if you planned to replace your windows for other reasons. 

Once these items have been addressed, it is worth looking at the source of heating. Alternatives to fossil fuels exist and although they are still comparatively rare in the UK they are becoming more common. The main ones being spoken about are heat pumps and hydrogen-fueled boilers. Heat pumps are the front-runner. They are essentially reverse refrigerators so they extract heat from outside and bring it into your home – even in cold weather. The outside source can be the air, ground or water with air likely to be the most relevant option for most domestic situations. They use electricity to power pumps and compressors to push a refrigerant gas around a closed system and can produce up to 3 or 4 units of heat for each unit of electricity they use. In most cases that would heat the water that travels to your radiators. So, as the country’s electricity supply increasingly turns to renewable sources such as wind and solar, the emissions of carbon will reduce. A good match would be solar panels on your roof alongside a heat pump. It is likely that some other alterations to the heating system in your house would be required as heat pumps don’t usually generate hot water at the same temperature as a traditional boiler so you may need large radiators for example.

Hydrogen as a fuel source is probably still a way off becoming a large-scale solution as a number of challenges need to be addressed. But it might come in time. The problem is we are constantly being told we don’t have much time to make the necessary changes to avoid climate disaster. Other options such as solar to directly heat water and district heating schemes, where a large generating plant produces heat that is pumped around a network of pipes taking heat to local properties. These are more common in parts of Europe but rare in the UK. And with the extensive work required to install them they are more likely to be an option for new housing developments.

Installation cost is a major obstacle to adoption of heat pumps and they are unlikely to generate long-term financial savings. The primary benefit is environmental and all of the associated benefits that flow from a cleaner environment. Hence, schemes such as the Green Homes Grant (unfortunately, recently cancelled by the Government and remaining funds transferred to a Local Authority scheme), that were set up to help with the up-front costs and the Renewable Heat Incentive, that will pay for heat generated much like the Feed in Tariff works for electricity. This Green Homes Grant scheme was plagued by various problems and it seems clear that if we have any chance of meeting our carbon targets, new, well-thought out and planned schemes will be required probably using a range of different incentives such as grants, tax adjustments, training and education. Let’s hope they arrive soon.

Whilst the move to increase the amount of electricity generated from renewable sources is positive, the transformation of our energy systems (domestic heat referred to here but also electricity use for other end uses such as electric vehicles) to become more reliant on electricity means that this needs to continue at pace.

So, like many of the major challenges we face a combination of individual action and larger Government and industry involvement is required.
Sources of advice and help:  Cosy Homes and Renewable Heat Incentive – see Energy Saving Trust  

*zero carbon can have several definitions and how you account for overall environmental impact, differing estimates of carbon emissions can be calculated